Today, various electronic devices exist. Such electronic devices include cellular phones, portable computers, MP3 players, personal digital assistants (PDAs), etc. A person may own one or all of such portable electronic devices and each portable electronic device may have a separate power supply system associated with it. The use of many different power supplies is not desirable, since power supplies (sometimes called “power bricks”) are often very bulky and cumbersome. For example, if a person owns a portable computer, a cellular phone, and an MP3 player, that person would also own three portable power supplies for those three portable electronic devices. If that person is traveling, it is quite cumbersome for that person to carry all of those portable power supplies with him.
In response to this need, some have developed “universal” power supplies. One such power supply is described in U.S. Pat. No. 5,838,554. This patent describes the use of a single power adapter for use with a plurality of different tips which can connect to different types of portable electronic devices. Each tip includes a different electrical component in it. In use, a tip is connected to the power adapter. The circuitry in the power adapter senses the electrical component in the tip and a feedback signal is provided to power circuitry containing a programmed IC chip. The power circuitry, in turn, provides a first output voltage. If a second tip with a different electrical component is selected, a different feedback signal is sent to the power circuitry and the power circuitry then produces a second output voltage associated with the second tip.
Although systems like the one described in U.S. Pat. No. 5,838,554 are effective in some instances, they could be improved. For example, the feedback circuitry that is used in such systems is complex and is relatively expensive to produce. The use of the above-described IC chip increases the cost of such power supplies.
What is desired is a simpler, more cost effective universal power supply solution. Embodiments of the invention address these and other problems, collectively and individually.